In general, electronic systems, such as mobile communication devices or consumer electronic devices, comprise digital circuits, which may be integrated circuits (digital ICs) to process data in digital format. However, within mobile communication devices or consumer electronic devices, also analog signals need to be processed. Therefore, these devices may comprise mixed signal circuits, which may be mixed signal integrated circuits (Mixed ICs). The mixed signal integrated circuits may provide conversion between analog signals and digital signals. The digital signals may be processed by the digital integrated circuits. Various analog signals and events may be processed within the mixed signal integrated circuit. After processing and A/D conversion, the signals may be routed to the digital integrated circuit.
Within mixed signal integrated circuits, analog-to-digital converters are embedded for converting the analog signals into digital signals. Digital-to-analog converters may as well be included to convert the digital signals into analog signals. The mixed signal integrated circuits connect the analog-to-digital converters with input terminals. The input terminals may be arranged to receive the analog signals. Multiple input terminals may be used. The signals on the input terminals may be multiplexed onto input terminals of the analog-to-digital converter. Within the analog-to-digital converter, the different signals may be converted within different time slots. The analog-to-digital converter may therefore convert various different analog signals into digital signals and may provide the digital signals to the digital integrated circuit.
The conversion of the analog signals into the digital signals needs to be controlled by the digital integrated circuits. Therefore, the mixed signal integrated circuits provide a serial interface. The serial interface may be responsible for transmitting control data and digital signals between the digital integrated circuit and the mixed signal integrated circuit. The digital signals may be processed within the digital integrated circuit and appropriate actions, such as control signals, may be generated or activated.
For controlling the mixed signal integrated circuit and the respective analog-to-digital converters, the software or the hardwired instructions within the digital integrated circuit may generate a write command. This write command may be a conversion command, instructing the analog-to-digital converter to convert analog input signals into digital signals. The write command may also comprise input channel selection data. This input channel selection data may be used within the analog-to-digital converter to select the respective input signal of one of various input terminals of the mixed signal integrated circuit.
Upon reception of the write command from the digital circuit via the serial interface, the analog-to-digital converter may execute an ordered conversion of the analog signal into a digital signal. The resulting digital signal may then be stored within a memory, located within the mixed signal integrated circuit, or located within an outside storage medium.
After the write command has been executed, the digital integrated circuit may be informed about finished execution. The digital integrated circuit may be informed about the finished execution, for example via the serial interface, a dedicated line, a dedicated interrupt or a dedicated signal, as well as by other information means. It may also be possible that the digital integrated circuit waits for a predefined latency time. The latency time may ensure completion of the conversion. The latency time may be larger than the actual processing time.
After conversion, the software of the digital integrated circuit, or hardwired instructions of the digital integrated circuit may generate a read command. This read command provides accessing the conversion results from the mixed signal integrated circuit. A read command is transferred to the mixed signal integrated circuit via the serial interface. Upon reception of the read command, the mixed-signal integrated circuit provides the conversion results from the memory through the serial interface to the digital integrated circuit. Within the digital integrated circuit, the digital signals may be used for further processing.
However, a drawback of these systems is that conversion of analog signals into digital signals and providing the digital signals to the digital integrated circuit requires the digital integrated circuit to access the mixed signal integrated circuit at least twice. The requirement of two temporal succeeding accesses may be imposed due to the serial interface. The serial interface is used to minimize the number of galvanic connection lines between the two circuits. As a serial interface only allows data transmission temporally serially, two separate accesses are required to transmit two separate control data sets, such as write and read command.
However, the use of the serial interface and the separate accesses imposes a drawback of latency for accessing converted analog signals. Latency between two conversions may be caused by having at least two mandatory serial accesses. Latency may also be caused due to jamming on the serial interface. Accessing the interface when the analog-to-digital converter or the mixed signal integrated circuit is accessed may not be possible. Therefore, reducing traffic within the interface would reduce latency. In addition, power consumption is increased, as accessing the mixed signal integrated circuit twice requires twice the amount of power as accessing the mixed signal integrated circuit once.